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Discussion Starter #1
A buddy of mine has a 05 brute 750 its been running greatfor the past month with the 2" snorkels he put on did not have to jet or adjust mix screws. Then he put on a HMF slip on a couple of days ago, ran great with out putting the 155/165 jets in that HMF sent the first time we went riding, then yesterday he starts it to go riding and its now sputtering and backfiring like crazy. so then we went ahead and put in the jets in (155f and 165r). we still cant get it to run right from about half throttle to full its just sputtering and popping. we spent hours yesterday changing jets and messing with the mixture srews. What else can we try. Thanks in advance.
 

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Sounds like the choke may be stuck... I would take the choke plungers our and clean them real good - then take the two springs off and pull them apart some before you put them back in. They have a tendency to loose their spring... Try that first if not - see below.

i would say the 155/165 is way too rich... and thats a big jump in jet sizes. Usually there should only be about 4 sizes between the two.
Did you try to go down in jet size any? Also where do you ahve the needles set at?

I would suggest 138/142 with needles on the third notch - 1 shim under the clip - 2.25-2.5 turns on mixture screw...

First before you do anything else - check the two choke plungers... they are on the right side of the carb and have a bracket with one screw holding them in - take the bracket off and pull them straight out. hit them as well as the choke holes with some carb cleaner... If this does the trick - dont use the choke anymore. It'll just do the same thing in the future. You can choke it manually by covering the air intake snork until it fires...

good luck.... let us know.
 

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Discussion Starter #3
sorry but what do ou mean when u say needles on the third notch and 1 shim under the clip?
 

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Discussion Starter #4
ok we have now went back to stock jets 158/152, 2 1/2 turns, and stock exhaust and did the whole pluger thing u told us to try and nothing changed. we did not mess with the needles cause we were not sure what u meant by shimming the clip and so forth.
 

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It doesnt sound like the choke to me. My experience with the choke was the exact opposite would spit and sputter UNTIL full throttle and then it will run good.
 

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Discussion Starter #6
Now we have 140/145 jets, and the mixture screws at 2.25 turns. it is still sputtering, popping. is it something else that we can check, maybe electrical or something.
 

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Belt reset?
 

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Belt reset?

That was my thought, how many hours are on the bike?.....if there is 100 to 110 hours, then your problem is most likely the belt reset. Check to see if the belt light is flashing, if it is, then that is your problem. just my .02
 

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Discussion Starter #9
ok the belt light was flashing, tried to reset but its still flashing
 

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Did it reset?

Try it again. Unless the belt is f!ked or very loose, it should start and not flash at first.

And it it does need to be reset, take your CVT cover off and inspect it anyway.
 

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There is another thread already posted about 2 or 3 down from this one with the instructions to reset the belt. Check it out
 

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Discussion Starter #13
Ok guys my buddy did put a belt in the other day when he put the exhaust on also. so i just went out and pulled the belt housing and sure enough the switch was off. i put the housing back on and reset the light and of course it worked perfect bike is now running good maybe some small adjust ment on the mixture screws again and we'll be good. Now i feel dumb but i guess we gotta learn some how. You guys are great Thanks a lot for the help.
 

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No problem, thats why we all are here, to help one another.
 

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We all feel warm and fuzzy now!!

Good to hear it was nothing serious.

Don't feel bad, some of the "pro's" have put the belt on backwards.....lol
 

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w00t!!
 

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Did you get the answer to what I was talking about as far as the needles and shims?

If not - each carb has its own needle. The needles allow you to fatten up (rich) or lean out the amount of gas that flows thru the main jet. There are different settings on each needle that will allow you to raise or lower the needle in the main jet. Lowering the clip on the needle will allow more gas to flow - raising the needle will lesson the flow of gas (drops the needle futher in the main jet). There are also 2 shims (small washers) that act as a half clip adjustments.

Hope this helps!!

Glad you guys figured it out! Let us konw if we can help in the future!
 
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